from flask import (
    Blueprint,
    abort,
    after_this_request,
    flash,
    redirect,
    render_template,
    request,
    send_file,
    url_for,
    current_app,
)
from flask_login import current_user, login_required
from functools import wraps
import os
import sqlite3
import tempfile
from datetime import datetime
from sqlalchemy.engine import make_url

from app.extensions import db
from app.models import Note, NoteType, Subject, User

admin_bp = Blueprint("admin", __name__)


def admin_required(f):
    @wraps(f)
    @login_required
    def decorated_function(*args, **kwargs):
        if not current_user.is_admin:
            return redirect(url_for("admin.verify"))
        return f(*args, **kwargs)

    return decorated_function


@admin_bp.route("/")
@admin_required
def dashboard():
    users_count = User.query.count()
    notes_count = Note.query.count()
    subjects_count = Subject.query.count()
    note_types_count = NoteType.query.count()

    return render_template(
        "admin/dashboard.html",
        users_count=users_count,
        notes_count=notes_count,
        subjects_count=subjects_count,
        note_types_count=note_types_count,
    )


@admin_bp.route("/verify", methods=["GET", "POST"])
@login_required
def verify():
    if current_user.is_admin:
        return redirect(url_for("admin.dashboard"))

    if request.method == "POST":
        code = request.form.get("code", "").strip()
        if code == current_app.config["ADMIN_SECRET_CODE"]:
            current_user.is_admin = True
            db.session.commit()
            return redirect(url_for("admin.dashboard"))
        else:
            pass

    return render_template("admin/verify.html")


@admin_bp.route("/subjects")
@admin_required
def subjects():
    subjects = Subject.query.order_by(Subject.name.asc()).all()
    return render_template("admin/subjects.html", subjects=subjects)


@admin_bp.route("/subjects/add", methods=["POST"])
@admin_required
def add_subject():
    name = request.form.get("name", "").strip()
    if name:
        existing = Subject.query.filter_by(name=name).first()
        if not existing:
            subject = Subject(name=name)
            db.session.add(subject)
            db.session.commit()
        else:
            pass
    return redirect(url_for("admin.subjects"))


@admin_bp.route("/subjects/update/<int:id>", methods=["POST"])
@admin_required
def update_subject(id):
    subject = Subject.query.get_or_404(id)
    name = request.form.get("name", "").strip()
    if not name:
        return redirect(url_for("admin.subjects"))

    existing = Subject.query.filter_by(name=name).first()
    if existing and existing.id != subject.id:
        return redirect(url_for("admin.subjects"))

    subject.name = name
    db.session.commit()
    return redirect(url_for("admin.subjects"))


@admin_bp.route("/subjects/delete/<int:id>", methods=["POST"])
@admin_required
def delete_subject(id):
    subject = Subject.query.get_or_404(id)
    db.session.delete(subject)
    db.session.commit()
    return redirect(url_for("admin.subjects"))


@admin_bp.route("/note-types")
@admin_required
def note_types():
    note_types = NoteType.query.order_by(NoteType.name.asc()).all()
    return render_template("admin/note_types.html", note_types=note_types)


@admin_bp.route("/note-types/add", methods=["POST"])
@admin_required
def add_note_type():
    name = request.form.get("name", "").strip()
    if name:
        existing = NoteType.query.filter_by(name=name).first()
        if not existing:
            note_type = NoteType(name=name)
            db.session.add(note_type)
            db.session.commit()
        else:
            pass
    return redirect(url_for("admin.note_types"))


@admin_bp.route("/note-types/update/<int:id>", methods=["POST"])
@admin_required
def update_note_type(id):
    note_type = NoteType.query.get_or_404(id)
    name = request.form.get("name", "").strip()
    if not name:
        return redirect(url_for("admin.note_types"))

    existing = NoteType.query.filter_by(name=name).first()
    if existing and existing.id != note_type.id:
        return redirect(url_for("admin.note_types"))

    note_type.name = name
    db.session.commit()
    return redirect(url_for("admin.note_types"))


@admin_bp.route("/note-types/delete/<int:id>", methods=["POST"])
@admin_required
def delete_note_type(id):
    note_type = NoteType.query.get_or_404(id)
    db.session.delete(note_type)
    db.session.commit()
    return redirect(url_for("admin.note_types"))


@admin_bp.route("/notes")
@admin_required
def notes():
    notes = Note.query.order_by(Note.created_at.desc()).all()
    subjects = Subject.query.order_by(Subject.name.asc()).all()
    note_types = NoteType.query.order_by(NoteType.name.asc()).all()
    return render_template(
        "admin/notes.html", notes=notes, subjects=subjects, note_types=note_types
    )


@admin_bp.route("/notes/update/<int:id>", methods=["POST"])
@admin_required
def update_note(id):
    note = Note.query.get_or_404(id)

    title = request.form.get("title", "").strip()
    description = request.form.get("description", "").strip()
    subject_id = request.form.get("subject_id")
    note_type_id = request.form.get("note_type_id")
    link = request.form.get("link", "").strip()

    if not title or not subject_id or not note_type_id:
        return redirect(url_for("admin.notes"))

    subject = Subject.query.get(subject_id)
    note_type = NoteType.query.get(note_type_id)
    if not subject or not note_type:
        return redirect(url_for("admin.notes"))

    note.title = title
    note.description = description or None
    note.subject_id = subject.id
    note.note_type_id = note_type.id

    if note.original_link is not None and link:
        note.link = link
        note.original_link = link

    db.session.commit()
    return redirect(url_for("admin.notes"))


@admin_bp.route("/notes/delete/<int:id>", methods=["POST"])
@admin_required
def delete_note(id):
    note = Note.query.get_or_404(id)
    db.session.delete(note)
    db.session.commit()
    return redirect(url_for("admin.notes"))


@admin_bp.route("/users")
@admin_required
def users():
    users = User.query.all()
    return render_template("admin/users.html", users=users)


@admin_bp.route("/users/toggle-admin/<int:id>", methods=["POST"])
@admin_required
def toggle_admin(id):
    user = User.query.get_or_404(id)
    if user.id == current_user.id:
        pass
    else:
        user.is_admin = not user.is_admin
        db.session.commit()
    return redirect(url_for("admin.users"))


@admin_bp.route("/export-db")
@admin_required
def export_db():
    uri = current_app.config.get("SQLALCHEMY_DATABASE_URI", "")
    try:
        parsed = make_url(uri)
    except Exception:
        abort(400, "Invalid database URL.")

    if parsed.drivername != "sqlite":
        abort(400, "Export endpoint only supports SQLite source databases.")

    if not parsed.database or parsed.database == ":memory:":
        abort(400, "In-memory SQLite database cannot be exported.")

    db_path = parsed.database
    if not os.path.isabs(db_path):
        db_path = os.path.abspath(db_path)

    if not os.path.exists(db_path):
        abort(404, "Database file not found.")

    fd, backup_path = tempfile.mkstemp(prefix="porahobe_backup_", suffix=".db")
    os.close(fd)

    src = sqlite3.connect(db_path)
    dst = sqlite3.connect(backup_path)
    try:
        src.backup(dst)
    finally:
        src.close()
        dst.close()

    @after_this_request
    def _cleanup(response):
        try:
            os.remove(backup_path)
        except OSError:
            pass
        return response

    filename = f"porahobe_backup_{datetime.utcnow().strftime('%Y%m%d_%H%M%S')}.db"
    return send_file(backup_path, as_attachment=True, download_name=filename)